Telecommunications connections generally .span more than one network administrative domain and involve more than one hierarchical layer. When a fault or trouble is detected, it is important to isolate the domain in which the fault has occurred so that remedial actions can be taken promptly. When a connection involves different network administrations, it is critical to determine responsibility for repair, etc. Connections are continuously monitored by nodes exchanging specially designed monitoring signals among them. Monitoring functions can take the following modes: Near-End (NE), Far-End (FE) and Intermediate (Int.) monitoring, which will be described in detail below. Today, some long distance carriers use proprietary enhancements of known monitoring techniques to sectionalize trouble. There are no standard techniques which are accepted industry wide for sectionalizing trouble among networks.
The invention resides in the trouble sectionalization process which uses well accepted NE, FE and Int. functions which are largely standardized or in the public domain. U.S. Pat. No. 5,450,394, issued Sep. 12, 1995 (Gruber et al) describes in detail NE, FE and Int. monitoring functions in connection with ATM, Frame Relay, packet switched networks etc.
The process of the invention can sectionalize trouble on connections in hierarchical or layered telecommunication networks that use NE, FE and Int. monitoring functions. Examples are PDH (pleisiochronous digital hierarchy), SDH (synchronous digital hierarchy) and ATM networks, and certain interworking combinations of such networks.